Facilitation of female rat lordosis behavior by hypothalamic infusion of 5-HT(2A/2C) receptor agonists.
Ovariectomized rats were hormonally primed with 0.5 microg estradiol benzoate and 500 microg progesterone to produce two groups of rats differing in their lordosis behavior. Females with a lordosis to mount (L/M) ratio < 0.5 were used to test the hypothesis that 5-HT(2A/2C) receptor agonists could facilitate lordosis behavior. Females with L/M ratios > or = 0.5 were used to evaluate the potential suppressive effect of 5-HT(2A/2C) receptor compounds. Lordosis behavior was examined following bilateral infusion of drugs into the ventromedial nucleus of the hypothalamus (VMN). Drugs examined were the 5-HT(2A/2C) receptor agonist, (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCl (DOI), the 5-HT(2A/2C) receptor antagonist, 3-[2-[4-(4-fluorobenzoyl)-1-piperdinyl]ethyl]-2,4(1H,3H)-quinazoli nedione tartrate (ketanserin tartrate), and the non-selective 5-HT receptor agents, 2-(1-piperazinyl)quinoline dimaleate (quipazine) and N-(3-trifluoromethylphenyl)piperazine HCl (TFMPP). Drugs with agonist action at 5-HT(2A/2C) receptors increased lordosis behavior in rats with low sexual receptivity. The 5-HT(2A/2C) receptor antagonist, ketanserin, inhibited lordosis behavior in sexually receptive rats. DOI attenuated the lordosis-inhibiting effect of ketanserin, but ketanserin was less effective in preventing DOI from increasing lordosis behavior. These results strengthen prior inferences that activation of 5-HT(2A/2C) receptors can facilitate lordosis behavior and that the VMN is one site at which such facilitation can occur.
Wolf
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Department of Biology, Texas Woman's University, Denton 76204-5799, USA.
Caldarola-Pastuszka
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Uphouse
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D000662:Amphetamines / Q000494:pharmacology; D000818:Animals; D005260:Female; D007033:Hypothalamus, Middle / Q000187:drug effects*; D007263:Infusions, Parenteral; D007650:Ketanserin / Q000494:pharmacology*; D011187:Posture; D051381:Rats; D011916:Rats, Inbred F344; D012702:Serotonin Antagonists / Q000494:pharmacology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D012726:Sexual Behavior, Animal / Q000187:drug effects*
D000662:Amphetamines; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D007650:Ketanserin; C015952:4-iodo-2,5-dimethoxyphenylisopropylamine